Congrats on the 3G, John!

Favorite apps? Well they have to be free - lol. I currently have:

Pandora
NY Times
AIM
Labyrinth (remember this old game of skill?)
Meebo (pre AIM IM app)
AOL Radio
eBay
reQall (very cool - check it out)
Whrrl (has potential)
Cellfire (coupons, discounts!)
Mobile News (I like the icon)
iScopes
Flashlight (basically a white screen to help you see in the dark and because I am a geek)

As far as weather, I like Who is Hot from Weather Underground. It's a slick little interface that shows a pic of your contact, their name and home city, the current temp and an icon showing current conditions. Pressing the icon delves into deeper weather detail (lots).

EDIT to add: Just looked at Shazam and read the reviews. Seems like an amazing app. Do you find it really works?